Various types of fishing tools are used in wells to retrieve tools, tubulars, casing, or other components that become stuck in a well. In a typical technique, a drillpipe lowers a fishing tool into the well, and a grapple at the end of the tool engages the stuck component. An upward force on the drillpipe can then dislodge the component. In other techniques, jars that are hydraulically or mechanically powered can generate a jarring force to dislodge the stuck component.
For example, casing can become stuck in the well and may need to be retrieved. Traditional removal of the stuck casing is done either with pilot milling, pulling the casing free with jarring action, and then steady pulling applied through the drillpipe and the derrick's draw work. Milling is very time consuming and labor intensive. Additionally, using jars to deliver a retrieving force does not effectively retrieve mud stuck casing.
To deal with stuck casing, pulling tools or casing jacks, such as those available from HOMCO, Wilson Downhole, Houston Engineers, and others, have been used for some time in the past. As one example, a downhole force generating tool disclosed in U.S. Pat. No. 5,070,941 has an anchor and a piston/cylinder arrangement.
In another example, U.S. Pat. No. 8,365,826 discloses a hydraulically powered fishing tool that can be used to retrieve another tool or tubular stuck in a well. The fishing tool is supported in a well on a workstring and has a mandrel with a fishing device that engages stuck tool or tubular in the well. An anchor axially fixes the position of the tool in the well, and pistons disposed on the tool above the anchor move the mandrel so the fishing device on the end of the mandrel can be moved axially and can dislodge the stuck tool or tubular.
Older systems use anchoring and pulling that is much too weak to handle the pull loads experienced in wells today. Today, Wellbore A/S of Norway has developed a Down Hole Power Tool (DHPT) that uses the hydraulically powered fishing tool disclosed in U.S. Pat. No. 8,365,826 to retrieve casing. However, the fishing tool mentioned above has the anchor section disposed below the pull section. During operation, the pulling load must pass through the anchor section. Additionally, any torque that is needed to be transmitted downhole through the tool is done through the internal dimensions of the tool's members.
Although most stuck components, such as casing, can be dislodged using the above techniques and tools, some stuck components may require other means to be retrieved and may need techniques that avoid damaging the stuck component or other elements in the well.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.